Nubbed elastic yarn and method of making same



June 18, 1968 D J MCCARTHY ET AL 3,388,546

NUBBED ELASTIC YARN AND METHOD OF MAKING SAME Filed Nov. 16, 1966 FIG 3 United States Patent 01 ice 3,383,545 Patented June 18, 1968 3,388,546 NUBBED ELASTKC YARN AND METHOD OF MAKING SAME Donald J. McCarthy, South Easton, and Preston F. Marshall, Walpole, Mass, assignors to The Kendall Company, Boston, Mass, a corporation of Massachusetts Filed Nov. 16, 1966, Ser. No. 594,746 7 Claims. (Cl. 57-152) ABSTRACT OF THE DISCLQSURE A novelty yarn having an elastomeric core strand in parallel arrangement with a nubbed yarn and said elastomeric core strand and said nubbed yarn being wrapped with a covering strand. The said nubbed yarn formed by wrapping a core with wrapping strand disposed to form double-back loops on said core.

This invention relates to composite wrapped elastic yarns of limited extensibility, and to a process for producing such yarns. More particularly it relates to such elastic yarns which have a nubbed, pebbled, or specky surface texture. Such yarns are of commercial utility in enhancing the surface appearance of fabrics woven or knitted therefrom, such as bathing suits and other elastic garments, ornamental elastic Webbings, and the like.

customarily, a nubbed or pebbled appearance is imparted to elastic textiles by inlaying a conventional nubbed yarn together with a wrapped elastic-cored yarn in a knitting process, or by alternating picks of a wrapped elasticcored yarn with one or more picks of conventional nubbed yarns. By the process of this invention, a nubbed aspect is provided by the elastic yarn itself, and due to the overwrapping, the nubs are locked into place along the length of the yarn and are not subject to slippage.

In US. Patents 3,076,307 and 3,280,546 there are described methods of forming nubbed or slubbed yarns, wherein a wrapping strand is disposed around a core strand in doubled-back loop form, the wrapping strand possessing no net true twist around the core strand. This is done by introducing the wrapping strand, preferably tangentially, to the core strand as the latter is being passed through a generally cylindrical vortex chamber which contains a whirling body of fluid. Under the conditions set forth in the patent and in the application mentioned above, the wrapping strand may be disposed around the core strand in an intermittent manner, so that the wrapped yarn has thick and thin segments along its length. Such yarns are sometimes called variable denier yarns, since the weight of a unit length of yarn will vary from segment to segment. Since the process of this invention, which involves an overwrapping operation, seems to accentuate the nub-like aspect of the yarn irregularities, such yarns will be called nubbed yarns, and the final product a nubbed elastic yarn, in this specification.

Basically, the yarn of the present invention is produced as follows:

(1) Extending an elastomeric core strand to a predetermined length.

(2) Combining with the extended elastomeric strand a nubbed yarn produced according to US. Patent No. 3,076,307 or US. application Ser. No. 374,743, now US. Patent No. 3,280,546, in parallel relation to the elastomeric strand.

(3) Wrapping the elastic strand and the nubbed yarn together in a conventional elastic yarn wrapping operation.

The elastomeric core strand may be of rubber, or of synthetic elastomeric material such as spandex. In general, such strands are capable of five hundred to eight hundred percent elongation, with rapid and substantially complete recovery when the elongating stress is removed.

The invention will be better understood by reference to the following description and drawings, in which:

FIGURE 1 represents a nubbed elastic yarn produced by this invention.

FIGURE 2 is another yarn produced by this invention.

FIGURE 3 is a schematic diagram of a process suitable for carrying out the process of this invention.

Referring to FIGURE 3, an elastomeric core strand 30, from supply package 32, is fed over star-wheels 34 and 36 and thence to a conventional hollow-spindle double-covering operation. The covering yarn supply, 46 and 48, and the actual covering mechanisms, are conventional. The take-up star-wheel 38 is geared to rotate more rapidly than the feed wheels 34 and 36: the resultant draft on the elastomeric core strand 30 means that said strand is under tension in the covering process, and that the elastomeric core in the final yarn is in extension, to provide the power desired for elastic garments.

To produce the yarn of FIGURE 1, a nubbed substantially inextensible falsely-wrapped yarn 40, made according to the processes set forth in US. Patents No. 3,076,- 307 or 3,280,546 is fed from supply roll 42 through a convenient guide 44 into parallel arrangement with the extended core yarn 30 before the first covering yarn is applied. By this process, both covering yarns are wrapped with true twist around both the elastomeric core strand and the nubbed inextensible strand, and the composite elastic yarn of FIGURE 1 results.

In FIGURE 1, the resultant yarn is shown as consisting of an elastomeric core strand 10 and a nubbed, substantially inextensible strand 12, in generally parallel arrangement, both covered or overwrapped by a pair of covering yarns 18 and 20. The nubbed strand 12, being inextensible, may be regarded as a novel form of stay strand, providing a decorative effect in the final yarn or fabric as well as serving the function of limiting the eventual elongation potential of the final composite yarn. As shown in FIGURE 1, the nubbed strand 12 consists of an inextensible core strand 14, around which there is disposed a wrapping strand '16, said wrapping strand being wrapped around the core strand 14 in the form of doubled-back loops having no net true twist around the core strand. At intervals, the wrapping strand 16 is aggregated into thick places or nubs which stand out from the core strand radially thereto.

Surprisingly, these nubs are not covered and obscured by the covering process in creating the yarn of FIGURE 1. (In general, the word wrapping will be used in this application to refer to the operation whereby a strand such as 16 is wrapped around a core strand 14 to form a nubbed yarn. The term covering will be used to denote the application of one or more strands, 1'8 and 20, to the nubbed yarn and an elastomeric core yarn held in parallel arrangement.) This unexpected persistence of the nubs of the yarn 12 into the final product, despite the doublecovering operation, may in part be attributed to the fact that the nubs formed in yarns made according to US. Patents No. 3,076,307 and 3,280,546 stand out from the core yarn, and the filaments comprising the nub are radially disposed to the core strand. There is thus a blossoming effect, with the base of the nub generally smaller in diameter than the top. In this manner, the yarn of FIGURE 1 is decorated at intervals with nubs 22, held in place but not obscured by the covering strands 18 and 20.

An accentuated decorative effect can be obtained if the nubbed stay strand of FIGURE 3 is not fed into the lower position to be covered by both covering strands, as shown, but is fed at position of FIGURE 3, so that the elastomeric core strand 30 has one covering yarn applied from the covering supply package 46. Means for this alternative method for feeding the nubbed stay strand will be obvious to those in the art, and are not shown. The once-covered yarn is then provided with a second covering from the supply package 48.

The result of this alternative process is the yarn of FIG- URE 2, wherein the numbered indicia have the same meaning as in the yarn of FIGURE 1. Referring to FIG- URE 2, the general spacing and appearance of the nubs 22 are about the same as are characteristic of FIGURE 1. However, since only one covering strand lies outside of the nubbed stay yarn 12, the Wrapping strand 16 associated with the stay yarn core strand 14 is pinched or compressed into a series of small filamentary bundles 24, which, like the nubs 22 originally associated with the yarn 12, extend outward from the composite yarn. These filamentary aggregates 24 are small in comparison with the size of the nubs 22, and are of the size usually associated with what are called seed, speck, or fleck yarns. They tend to circle spirally around the final composite yarn, and although they may be found occasionally in the yarn of FIGURE 1, they are especially prominent in the yarn of FIGURE 2.

The invention will be illustrated by the following example.

Example 1 Using the double covering process, a number 40 extruded rubber cord strand was brought into parallel arrangement, according to FIGURE 3, with an all-white nubbed stay yarn which consisted of a denier, 34 filament nylon core strand, each yard of which was wrapped with approximately 4 yards of denier, 2O filament acetate. The nubbed stay yarn had a total denier of about 370, with nubs distributed approximately one inch apart, and the wrapping strand was disposed around the core strand in the form of doubled-back loops with no net true twist around the core strand, the loops being at intervals aggregated into nubs.

The differential speed between star rolls 36 and 38 was such that the rubber strand 30 was elongated by approximately 150% in the covering process. The bottom cover was a green l8s cotton yarn, the top cover a three-ply 18s (6s equivalent) green cotton yarn. The speed of covering was such as to yield 200 yards per hour of covered yarn, with both covering yarns being applied that approximately 3.5 yards of each cover yarn was present in each yard of final composite nubbed. elastic yarn.

The yarn resembled the one depicted in FIGURE 1, with white filamentary nubs 22 emergent from the green covering yarns 18 and 20. The conditions of processing were such that the final yarn had an extensibility of about When woven as the warp in a conventional elastic webbing, a very pleasing decorative effect was obtained with the yarn of Example 1.

Having thus described our invention, we claim:

1. A novelty elastic yarn with a nubbed surface texture and of controlled elongation which comprises an elastomeric core strand in generally parallel arrangement with a nubbed, wrapped, substantially inextensible stay strand,

said stay strand comprising a core strand with at least one Wrapping strand disposed thereabout in the form of doubled-back loops,

said wrapping strand possessing no net true twist around said core strand, and being at intervals aggregated 4: into nubs along the length of said stay strand, said stay strand and said elastomeric core strand being covered by at least one covering strand disposed around said stay strand and said elastomeric core strand with true twist.

2. The yarn according to claim 1 wherein both the stay strand and the elastomeric core strand are covered with two covering strands disposed with opposite twists around said stay strand and said elastomeric core strand.

3. A novelty elastic yarn of controlled elongation and characterized by a surface texture comprising nubs and flecks, which comprises an elastomeric core strand covered with at least one Covering strand truly twisted thereabout,

a nubbed, wrapped substantially inextensible stay strand in generally parallel arrangement with the covered elastomeric strand,

said stay strand comprising a core strand with at least one wrapping strand disposed thereabout in the form of doubled-back loops,

said wrapping strand possessing no net true twist around said core strand, and being at intervals aggregated into nubs along the length of said stay strand, said stay strand and said covered elastomeric strand being in generally parallel arrangement and both being covered by at least one additional covering strand disposed with true twist around said stay strand and said covered elastorneric strand.

4. The yarn of claim 1 in which the wrapping strand disposed around the core of the stay strand is of a different color from the covering strand which is twisted about both the elastomeric strand and the stay strand.

5. The process of producing a novelty elastic yarn with a nubbed surface texture and of limited extensibility which comprises preparing a substantially inextensible wrapped and nubbed stay strand comprising at least one wrapping strand disposed around a core strand in the form of double-back loops possessing no net true twist around said core strand,

and said wrapping strand being at intervals aggregated into nubs along the length of said stay strand,

combining said nubbed stay strand in generally parallel arrangement with a partially-extended elastomeric core strand,

covering the combined stay strand and elastomeric core strand with at least one covering strand truly twisted about said stay strand and said elastomeric core strand,

and allowing the composite covered yarn to relax.

6. The process according to claim 5 where a pair of covering strands are disposed about the combined stay strand and extended elastomeric strand with true twist, each covering strand of said pair of strands being twisted around the combined stay strand and extended elastomeric strand in a direction opposed to the other covering strand.

7. The process of producing a novelty elastic yarn of controlled elongation and characterized by a surface texture comprising nubs and flecks which comprises covering a partially-extended elastomeric core strand with at least one covering strand truly twisted thereabout;

preparing a substantially inextensible wrapped and nubbed stay strand comprising at least one wrapping strand disposed around a core strand in the form of doubled-back loops possessing no net true twist around said core strand,

said wrapping strand being at intervals aggregated into nubs along the length of said stay strand;

combining said nubbed stay strand with said covered elastomeric strand while the latter strand is partiallyextended,

covering the combined stay strand and the elastorneric core strand with at least one covering strand truly References Cited UNITED STATES PATENTS Smith et al. 57-152 XR Alderfer 57 152 Rupprecht 57152 Marshall 57-152 XR 10 6 Marshall 57-144 XR Bridgeman et al. 57-17 XR Spicer et al. 57144 Neel 57-152 Spicer et a1. 57-152 Marshall 57-160 FRANK J. COHEN, Primary Examiner.

D. E. WATKINS, Assistant Examiner. 

